Patent application title: GIVEAWAY WEIGHT REDUCTION

Abstract:

A food processing system is provided for outputting groups of slices of a
food product, with each group having a weight greater than a
predetermined group weight threshold. The system includes a food slicing
machine (10) having control means (32) for regulating the thickness of
the slices cut by the machine so that they are cut according to the
current value of a slice size parameter. Means (26) are provided for
generating an under-weight signal responsive to the generation of any
groups of slices by the slicing machine having a weight less than the
predetermined group weight threshold, and an end-of-line weighing means
monitors the weight of groups of slices outputted by the system and
generates an end-of-line weight signal responsive thereto. The system is
arranged to identify any under-weight groups of slices so that their
weight can be increased by the addition of a further slice before being
outputted by the system and the control means (32) is arranged to receive
the end-of-line weight signal and the under-weight signal and determine
the value of the slice size parameter having regard to the signals. In
this way, the slice size parameter may be adjusted to minimise the amount
of give-away by the system.

Claims:

1. A food processing system for outputting groups of slices of a food
product with each group having a weight greater than a predetermined
group weight threshold, including:a food slicing machine having control
arrangement for regulating the thickness of the slices cut by the machine
so that the machine cuts slices according to the current value of a slice
size parameter;an under-weight signal generating apparatus responsive to
the generation of any groups of slices by the slicing machine having a
weight less than the predetermined group weight threshold; andan
end-of-line weighing arrangement at an end-of-line position for
monitoring the weight of groups of slices outputted by the system and
generating an end-of-line weight signal responsive thereto,wherein the
system is arranged to identify any under-weight groups of slices so that
their weight can be increased by the addition of a further slice before
being outputted by the system, and the control arrangement is arranged to
receive the end-of-line weight signal and the under-weight signal and to
determine the value of the slice size parameter having regard to these
signals, such that the value tends towards an optimal value of the
slicing parameter to minimise give-away at the end-of-line position.

2. A system of claim 1 wherein the under-weight signal generating
apparatus includes an input device for use by an operator upon detection
of a group of slices having a weight less than the predetermined group
weight threshold.

3. A system of claim 1 including a check-weight weighing arrangement for
monitoring the weight of groups of slices outputted by the slicing
machine, wherein the under-weight signal generating apparatus is the
check-weight weighing arrangement and the under-weight signal is
responsive to the weights of under-weight groups of slices measured by
the check-weight weighing arrangement.

4. A system of claim 1 wherein the under-weight signal is indicative of
the rate of production of groups of slices by the slicing machine which
have a weight less than the predetermined group weight threshold.

5. A system of claim 1 including:a separating arrangement for separating
groups of slices outputted by the slicing machine which have a weight
less than the predetermined group weight threshold from groups of slices
outputted by the slicing machine which have a weight greater than or
equal to the predetermined group weight threshold; anda make-weight
weighing arrangement for measuring the weight of a separated group of
slices which has a weight less than the predetermined group weight
threshold, wherein the under-weight signal generating apparatus is the
make-weight weighing arrangement and the under-weight signal is
responsive to the weights of groups of slices measured by the make-weight
weighing arrangement.

6. A food slicing machine for outputting groups of slices of a food
product with each group having a weight greater than a predetermined
group weight threshold, including a control arrangement for regulating
the thickness of the slices cut by the machine so that the machine cuts
slices according to the current value of a slice size parameter, wherein
the control arrangement is arranged to receive an under-weight rate
signal responsive to the rate of production of groups of slices by the
slicing machine which have a weight less than the predetermined group
weight threshold and to determine the current value of the slice size
parameter having regard to this signal.

7. A machine of claim 6 wherein the machine includes a check-weight
weighing arrangement for monitoring the weight of groups of slices
outputted by the slicing machine, and the under-weight rate signal is
generated by the check-weight weighing arrangement.

8. A machine of claim 7 wherein said predetermined value is greater than
zero.

9. A machine of claim 6 wherein the machine includes a check-weight
weighing arrangement for monitoring the weight of groups of slices
outputted by the slicing machine, and the under-weight rate signal is
generated by the check-weight arrangement.

10. A machine of claim 9 wherein the control arrangement is operable to
determine the current value of the slice size parameter having regard to
the under-weight rate signal such that the under-weight rate signal tends
towards a predetermined value.

11. A machine of claim 10 wherein said predetermined value is greater than
zero.

12. A method of slicing a food product using a food processing system
including a food slicing machine, comprising the steps of:cutting slices
according to a first value of a slice size parameter;receiving an
end-of-line signal which is responsive to the weight of groups of slices
outputted by the system;receiving an under-weight signal which is
responsive to the generation of any groups of slices by the slicing
machine having a weight less than a predetermined group weight threshold;
anddetermining a second value of the slice size parameter having regard
to these signals, wherein the second value is calculated such that the
slice size parameter tends towards an optimal value to minimise
give-away.

13. A method of slicing a food product using a food slicing machine,
comprising the steps of:cutting slices according to a first value of a
slice size parameter;receiving an under-weight rate signal responsive to
the rate of production of groups of slices by the slicing machine which
have a weight less than a predetermined group weight threshold;
anddetermining a second value of the slice size parameter having regard
to the under-weight rate signal.

14. A food processing system for outputting groups of slices of a food
product with each group having a weight greater than a predetermined
group weight threshold, including:a food slicing machine having control
means for regulating the thickness of the slices cut by the machine so
that the machine cuts slices according to the current value of a slice
size parameter;means for generating an under-weight signal responsive to
the generation of groups of slices by the slicing machine having a weight
less than the predetermined group weight threshold; andan end-of-line
weighing means for monitoring the weight of groups of slices outputted by
the system and generating an end-of-line weight signal responsive
thereto,wherein the system is arranged to enable to weight of
under-weight groups of slices to be increased by the addition of a
further slice before being outputted by the system, and the control means
is arranged to receive the end-of-line weight signal and the under-weight
signal and to determine the value of the slice size parameter having
regard to these signals.

15. A method of slicing a food product using a food processing system
including a food slicing machine, comprising the steps of:cutting slices
according to a first value of a slice size parameter;receiving an
end-of-line signal which is responsive to the weight of groups of slices
outputted by the system;receiving an under-weight signal which is
responsive to the generation of groups of slices by the slicing machine
having a weight less than a predetermined group weight threshold;
anddetermining a second value of the slice size parameter having regard
to these signals.

Description:

FIELD OF THE INVENTION

[0001]The present invention relates to systems for slicing food products
(such as bacon, cheese or cooked meat). More particularly, it relates to
systems configured to output groups of slices for sale in separate packs,
with each group having a weight greater than a predetermined group weight
threshold.

BACKGROUND TO THE INVENTION

[0002]Increasingly, food retailers and supermarkets in particular require
suppliers to provide packs of sliced food products of standard weights.
Labelling regulations may permit some deviation from the standard weights
indicated on packs but only within narrow tolerances.

[0003]It is therefore desirable for food suppliers to aim to provide packs
which just meet the associated weight requirements, minimising the extent
to which any minimum requirement is exceeded. Any such excess food
product included in a pack is often referred to as "give-away".

[0004]In view of the pressure to just satisfy a minimum requirement,
groups of slices are occasionally generated by a slicing machine which
are slightly below this minimum threshold. In known processing
arrangements, these "under-weight" groups are diverted out of the path to
the packaging process and to a separate station, sometimes referred to as
the "make-weight" station. An operator at the make-weight station adds an
additional slice to each under-weight group of slices and then returns
the group made up to an acceptable weight with the additional slice into
the path to the packaging process.

[0005]This process tends to increase give-away, as under-weight packs are
likely to fall short of the minimum threshold by an amount less than the
weight of an entire additional slice. For example, a slice of bacon may
typically weigh 20 g. If an under-weight group of slices only falls short
by 2 g, the under-weight group together with an additional slice created
at the make-weight station will include a give-away of 18 g. Given the
large number of under-weight packs likely to be generated by a processor
having a high throughput of food packs, the cumulative give-away is
substantial and therefore costly.

[0006]A food slicing machine is typically configured to cut each slice
from a log of food product according to the current value of a slice size
parameter, often referred to as the slicer "set point". If this parameter
is set too low, the make-weight station becomes inundated with
under-weight groups of slices and the operator at the make-weight station
can become overwhelmed. If the parameter is set too high, the amount of
give-away increases, making the process less cost efficient.

[0007]The physical properties of food products can vary in stability
depending on the type of food product to be sliced. A relatively
homogeneous product such as cheese has reasonably consistent properties,
whereas the properties of a less consistent, naturally formed product
such as bacon can vary significantly depending on a number of variables,
such as the lean-to-fat ratio, the temperature of the food product, its
brine content and the like. When slicing this type of product, the
optimum set point can vary from day to day and during the course of each
day. Careful monitoring and control of the set point is therefore
desirable to maximise the efficiency of the system during operation.

SUMMARY OF THE INVENTION

[0008]The present invention provides a food processing system for
outputting groups of slices of a food product with each group having a
weight greater than a predetermined group weight threshold, including:
[0009]a food slicing machine having a control arrangement for regulating
the thickness of the slices cut buy the machine so that the machine cuts
slices according to the current value of a slice size parameter; [0010]an
under-weight signal generating apparatus responsive to the generation of
any groups of slices by the slicing machine having a weight less than the
predetermined group weight threshold; and [0011]an end-of-line weighing
arrangement at an end-of-line position for monitoring the weight of
groups of slices outputted by the system and generating an end-of-line
weight signal responsive thereto, [0012]wherein the system is arranged to
identify any under-weight groups of slices so that their weight can be
increased by the addition of a further slice before being outputted by
the system, and the control arrangement is arranged to receive the
end-of-line weight signal and the under-weight signal and to determine
the value of the slice size parameter having regard to these signals,
such that the value tends towards an optimal value of the slicing
parameter to minimise give-away at the end-of-line position.

[0013]The slice size parameter may be slice thickness, or slice volume or
weight. Where a log of food product has a variable cross-section, the
slicing machine may include means for determining the area of the end
face at the end of the food product being cut. This then enables the
slice thickness to be calculated which generates a slice having the
desired slice volume or weight.

[0014]Whilst monitoring the output of an end-of-line weighing arrangement
alone would give an indication of the rate of food give-away, the
inventor has realised that this signal would not take into account the
influence of the make-weight function. As a make-weight function will
tend to generate groups including a significant amount of give-away due
to the coarseness of the "topping up" process carried out at the
make-weight station, generation of an increasing number of under-weight
groups will tend to create a vicious circle, leading to overloading of
the make-weight station.

[0015]As an increasing rate of groups is fed to the make-weight station,
the amount of give-away will increase as these groups are fed back into
the path to the packing station, past the end-of-line weighing
arrangement. The end-of-line weighing arrangement will indicate the
amount of give-away is increasing and therefore indicate that the slicing
set point should be reduced. This will only increase the number of groups
being sliced which are under-weight and therefore having to be diverted
to the make-weight station.

[0016]To address this problem, in a system according to the present
invention, the slicing machine control arrangement is responsive not only
to the end-of-line weight signal, but also an under-weight signal which
is related to the generation of under-weight groups of slices.

[0017]Using feedback signals in this manner, the control arrangement is
able to incrementally increase or decrease the current value of the slice
size parameter (the set point) so as to reduce the amount of give-away by
tending towards an optimum set point for the current operating conditions
of the slicing machine and current properties of the food product being
sliced, without inundating a make-weight function.

[0018]In a preferred embodiment of the invention, the under-weight signal
generating apparatus includes an input device for use by an operator at a
make-weight station, having regard to the weight of an under-weight group
or groups of slices received at the make-weight station and/or the rate
at which such groups are arriving at the make-weight station.

[0019]In another preferred embodiment, the under-weight signal generating
apparatus is a check-weight weighing arrangement, which monitors the
weight of the groups of slices generated by the slicing machine. The
under-weight signal is responsive to the weights of under-weight groups
of slices measured by the check-weight weighing arrangement. In this way,
generation of the under-weight signal may be automated.

[0020]The under-weight signal may represent the respective weights of
individual groups of under-weight slices. Alternatively, it may be
related in a more general way to the weight of under-weight groups. For
example, the under-weight signal may be indicative of the rate of
production of under-weight groups of slices by the slicing machine.

[0021]Preferably, the system includes a separating arrangement for
separating groups of slices outputted by the slicing machine which have a
weight less than the predetermined group weight threshold from groups of
slices outputted by the slicing machine which have a weight greater than
or equal to the predetermined group weight threshold; and a make-weight
weighing arrangement for measuring the weight of a separated group of
slices which has a weight less than the predetermined group weight
threshold, wherein the under-weight signal generating apparatus is the
make-weight weighing arrangement and the under-weight signal generating
apparatus is responsive to the weights of groups of slices measured by
the make-weight weighing arrangement.

[0022]The present invention further provides a food slicing machine for
outputting groups of slices of a food product with each group having a
weight greater than a predetermined group weight threshold, including a
control arrangement for regulating the thickness of the slices cut by the
machine so that the machine cuts slices according to the current value of
a slice size parameter, wherein the control arrangement is arranged to
receive an under-weight rate signal responsive to the rate of production
of groups of slices by the slicing machine which have a weight less than
the predetermined group weight threshold and to determine the current
value of the slice size parameter having regard to this signal.

[0023]The inventor has realised that the rate of production of
under-weight groups of slices which provides a good indication of how
efficiently the slicing system is operating, which can be employed by a
controller to adjust the slicing set point of the slicing machine.

[0024]In a preferred embodiment, the under-weight rate signal is generated
by the check-weight weighing arrangement, which monitors the weight of
groups of slices outputted by the slicing machine. It will though be
appreciated that the rate of production of groups of under-weight slices
may be detected at various locations in the system.

[0025]The control arrangement may be operable to determine the current
value of the slicing set point having regard to the under-weight rate
signal in such a way that the under-weight rate signal tends towards a
predetermined value. In some cases, it may be preferable for this
predetermined value to be greater than zero, with optimal control of the
system to minimise give-away involving a limited rate of generation of
under-weight groups of slices.

[0026]According to a further aspect, the invention provides a method of
slicing a food product using a food processing system including a food
slicing machine, comprising the steps of: [0027]cutting slices
according to the first value of a slice size parameter; [0028]receiving
an end-of-line signal which is responsive to the weight of groups of
slices outputted by the system; [0029]receiving an under-weight signal
which is responsive to the generation of any groups of slices by the
slicing machine having a weight less than a predetermined group weight
threshold; and [0030]determining a second value of the slice size
parameter having regard to these signals, wherein the second value is
calculated such that the slice size parameter tends towards an optimal
value to minimise give-away.

[0031]In addition, the invention also provides a method of slicing a food
product using a food slicing machine, comprising the steps of cutting
slices according to a first value of a slice size parameter; receiving an
under-weight rate signal responsive to the rate of production of groups
of slices by the slicing machine which have a weight less than a
predetermined group weight threshold; and determining a second value of
the slice size parameter having regard to the under-weight rate signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032]Embodiments of the invention will now be described by way of example
and with reference to the accompanying schematic drawings, wherein:

[0033]FIG. 1 shows a plan view of a food processing system according to an
embodiment of the invention; and

[0034]FIG. 2 is a side view of the system shown in FIG. 1.

DETAILED DESCRIPTION

[0035]The system shown in FIGS. 1 and 2 includes a food slicing machine 10
which outputs slices of a food product onto conveyer 12. This in turn
feeds groups of slices through a weighing station 14.

[0036]Groups of slices which are detected by the weighing station as
meeting predetermined weight requirements are passed on to an "on-weight"
conveyer 16 by a pivotable section of conveyer 18. Alternatively, groups
of slices which fall outside the predetermined weight requirements are
diverted by pivotable conveyer 18 and angled conveyer 20 on to an
"off-weight" conveyer 22.

[0037]In FIG. 2, pivotable conveyer 18 is shown in a lowered orientation,
which diverts groups of slices towards the off-weight conveyor. Its
alternative orientation in which groups of slices continue on to the
on-weight conveyer is shown by dashed lines (18').

[0038]Groups of slices travelling down the on-weight conveyor are carried
to a packaging station (not shown) for sealing into respective packs.
Groups of slices diverted on to the off-weight conveyor 22 are carried
down to a make-weight station 24 which includes a set of weighing scales
26.

[0039]Slicing machine 10 includes an inclined loading bed within a housing
30 for supporting a log of food product to be sliced. The log is fed
towards a rotating slicing blade (not shown) located at the lower end of
the loading bed. A control arrangement 32 is programmable to control the
operation of the slicing machine. It includes a display and control panel
to enable an operator to monitor its operation and enter commands as
appropriate.

[0040]A gripper engages the trailing end of the food product and feeds it
towards the slicing blade. The distance by which the product is fed past
the blade determines the slice thickness.

[0041]The slicer may be programmed to slice a given food product at a
given "set point". This set point is a parameter relating to the size of
the slices to be cut. It may, for example, represent a desired slice
thickness. Alternatively, in a system able to measure the cross-sectional
area of the end face of the food product which is being cut, the set
point may represent a desired slice volume or weight. On the basis of the
measured cross-sectional area, the control arrangement determines the
slice thickness needed to achieve the set point volume or weight and
controls the slicer accordingly.

[0042]In the embodiment of the invention shown in FIGS. 1 and 2, the
weighing scales 26 at the make-weight station include a control panel for
use by an operator 28. Using the scales, the operator is able to
determine how far below the desired weight the off-weight groups of
slices received are. The operator can then use the control panel to
indicate the shortfall of individual off-weight groups. Alternatively,
the operator may indicate via the control panel that the rate of
generation of off-weight groups is too high or too low and/or the current
set point should be increased or decreased.

[0043]On-weight conveyor 16 carries groups of slices beyond the
make-weight station, towards an end-of-line weighing arrangement (not
shown). This weighing arrangement is therefore able to weigh slices
carried directly to it by the on-weight conveyor, and also groups of
slices placed onto the on-weight conveyor by the operator at the
make-weight station. The end-of-line weighing arrangement may monitor the
weight of groups of slices before or after they have been individually
packaged.

[0044]The end-of-line weighing arrangement is communicatively coupled to
the control arrangement 32 to enable transmission of an end-of-line
weight signal from the end-of-line weighing arrangement thereto. The
weighing station 14 and weighing scales 26 are similarly coupled to the
control arrangement for feeding back respective signals.

[0045]The control arrangement is programmed to determine the value of the
slice size parameter (set point) having regard to the signals it receives
with a view to minimising the amount of give-away generated by the
system.

[0046]It will be appreciated that operations carried out at the
make-weight station could be automated to greater extent, for example by
the use of one or more robotic arms to manipulate individual slices or
groups of slices to create on-weight groups and place them onto the
on-weight conveyor. Furthermore, in an alternative configuration,
under-weight groups could remain on the conveyor 16 and be "topped up" by
a robotic arm or arms which transfer an additional slice onto each
under-weight group as it travels towards, or is located at, the packing
station.